JP2001316163A - Method for manufacturing fiber-reinforced calcium silicate body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for improving surface smoothness, adherence of a coat, solvent-absorbing rate, fluffing of a fiber-reinforced calcium silicate formed body for a decorative board. SOLUTION: The fiber-reinforced calcium silicate formed body compounded with at least a bleached chemical pulp of <=10 wt.%, preferably 2-7 wt.%, more preferably 3-5 wt.% as a reinforcing fiber is coated with a liquid paint, thanks to controlled solvent (water) absorption speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber-reinforced calcium silicate molded article widely used as a building material or a decorative base material, and a method for producing the same.

[0002]

2. Description of the Related Art A typical example of a calcium silicate molded article containing a reinforcing fiber is a fiber reinforced calcium silicate plate. The fiber reinforced calcium silicate plate is formed by mixing a slurry of calcareous raw material, siliceous raw material, a raw material composed of reinforcing fibers and additives and water and dispersing it into a plate by pressure molding or papermaking method. After pressure molding, it is cured by autoclaving and manufactured.

Hitherto, as a reinforcing fiber, wood pulp using cellulose or hardwood as raw material, waste paper using cellulose pulp or wood pulp has been frequently used. Recently, as shown in JP-A-10-29844, fine fibrils are used. And Japanese Patent Application Laid-Open No. 7-286401 discloses a hydraulic inorganic papermaking product in which cellulose fibers having a short fiber length, pulp, and organic synthetic long fibers are used as reinforcing fibers. Is disclosed. On the other hand, most of these molded products are used as architectural materials after the surfaces thereof are subjected to painting, decorative processing and the like.

[0004]

However, when these molded articles are subjected to painting or decorative processing, their performance as a base material has many problems. For example, when wood pulp is used, there is a problem in the ability of the wood pulp to capture powder, and the surface smoothness of the molded product is poor. Also, due to the influence of wood pulp, the bonding strength with the calcium silicate matrix is weak, and the wood pulp itself and organic synthetic fibers protrude (fuzz) on the base material surface, and the paint absorption rate (solvent absorption rate) is fast, When a paint of the paint film type is used, a large amount of paint must be applied in order to obtain the desired paint film adhesion. On the other hand, there is a problem that only an impregnated type paint can be used as a paint applied to the surface of a calcium silicate molded body.

For this reason, when the surface smoothness is poor, the surface of the substrate is polished. Even if the surface of the substrate is polished, the surface smoothness is slightly effective, but the surface of the substrate is fuzzy. The problem remains. Further, when the base material is subjected to coating or decorative processing, there is a problem that the fluffing causes roughness on the decorative surface. JP Hei 10
No. 29844 uses fine fibrillated cellulose, so that the solvent absorption (water absorption) rate is high, and the surface smoothness and the yield still have problems. In JP-A-7-286401, although the papermaking property or the reinforcing property is improved, it is insufficient in terms of the surface smoothness and the high absorption rate of the paint (solvent absorption rate).

On the other hand, in the field of paper and paperboard, the production amount exceeds 30 million tons / year, and the production amount of printing paper accounts for 30% or more thereof. Effective utilization and incineration are becoming problems from the viewpoint of global warming.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a conventional calcium silicate molded article containing a reinforcing fiber, which has problems such as poor retentivity of the reinforcing fiber, solvent absorption rate, and poor surface smoothness, and recycling of used printing paper (effective utilization). It is an object of the present invention to provide a fiber-reinforced calcium silicate molded article which solves the above-mentioned problem and a method for producing the same.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have achieved the above-mentioned conventional problems.
That is, in the first invention, in a calcium silicate molded article containing reinforcing fibers, the chemical pulp is exposed to at least a part of the reinforcing fibers to 1 to 10% by mass, preferably 2 to 7% by mass, more preferably 3 to 7% by mass. The present invention provides a fiber-reinforced calcium silicate molded article containing 5% by mass and having a solvent absorption (water absorption) time of 20 to 35 seconds.

In a second aspect of the present invention, the bleached chemical pulp is waste paper of printing paper containing 70% by mass or more, preferably 90% by mass or more of the bleached chemical pulp. It provides the body.

[0010] The third invention is a method of mixing and dispersing bleached chemical pulp which has been beaten in advance, calcareous raw material, siliceous raw material, reinforcing fiber (excluding bleached chemical pulp), and additives and water, and forming a sheet by a papermaking method. The present invention provides a method for producing the above fiber-reinforced calcium silicate molded product, which is formed into a shape and, if necessary, further subjected to pressure molding, and then autoclaved.

[0011] A fourth invention is to disperse bleached chemical pulp which has been beaten in advance, calcareous raw material, siliceous raw material, reinforcing fiber (excluding bleached chemical pulp) and additives and water, and form the mixture by a dewatering press. The present invention also provides a method for producing the above fiber-reinforced calcium silicate molded body, which is subjected to autoclave curing.

In addition to solving the problems of the conventional fiber-reinforced calcium silicate molded product, it is suitable as a cosmetic base material for building materials, that is, without using chemicals having a substantially water-repellent (solvent) action. The purpose of the present invention is to improve the problems of smoothness, solvent (paint) absorption rate, coating film adhesion, and fluffing by using bleached chemical pulp or waste paper containing the same, and at the same time, to control their suitability.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The fiber-reinforced calcium silicate molded article of the present invention is suitable as a cosmetic base material for building materials, that is, has a smooth surface without using chemicals having a substantially water-repellent (solvent) action. Characteristics of solvent, paint (coating) absorption, coating film adhesion, and fluffing are improved by using bleached chemical pulp or waste paper containing it, and at the same time, their suitability can be controlled. Hereinafter, the fiber-reinforced calcium silicate molded article of the present invention and a method for producing the same will be described.

The bleached chemical pulp referred to in the present invention is a pulp obtained by subjecting organic components such as lignin, hemicellulose, coloring matter and tannin contained in the pulp raw material to a decomposition treatment with a bleaching powder. Since these bleached chemical pulp are decomposed and reduced by the oxidative decomposition and chlorination reaction of the above organic components contained in the pulp raw material, they have good bonding strength with the calcium silicate matrix and good dispersibility. It is preferable since it has no effect on the production system of the calcium silicate molded article. At this time, the content of the bleached chemical pulp is 1 to 10% by mass, preferably 2 to 7% by mass, and 3 to 5% by mass based on the total solid content of the calcium silicate molded body.
% By mass. If the content is 10% by mass or more, there is a problem in fire resistance and nonflammability.

Furthermore, waste paper of printing paper mainly containing the bleached chemical pulp is generated due to the effect of the surface smoothness and the influence on the reaction system being small and the high solvent absorption rate of the prior art. This is preferable because problems can be improved. The bleached chemical pulp content of the waste paper of the printing paper is 70% by mass or more, preferably 9% by mass, based on the total solid content of the waste paper.
When the content is 0% by mass or more and less than 70% by mass, the bonding strength to the calcium silicate matrix and the dispersibility are reduced, and the effects on surface smoothness, solvent (paint) absorption speed, coating film adhesion, and fluffing are reduced. .

The bleaching of the bleached chemical pulp is carried out according to a conventional method, for example, using only a pulper disintegrator, a beater beater, a disc refiner, or the like, and only the bleached chemical pulp or printing paper waste paper, or the bleached chemical pulp or printing paper waste paper and wood pulp. Or cellulose pulp and water are mixed and dispersed, and disintegrated into a slurry having a concentration of 2 to 15% by mass, preferably 3 to 8% by mass, and then treated using a beater beater, a rod mill, or a disk crusher or the like. The beating process can be performed by appropriately adjusting the number of times. At this time, the freeness of the mixed pulp fiber is 7 according to JIS P8121.
It is preferable that the beating treatment is performed so as to be 0 to 350 ml, preferably 80 to 200 ml.

Particularly, it is preferable to use in combination with unused wood pulp or cellulose pulp in view of the strength of the fiber-reinforced calcium silicate molded article. In this case, the ratio of bleached chemical pulp to unused wood pulp or cellulose pulp is 6 by mass.
/ 4 to 2/8 are preferred. Unused woody pulp as used herein refers to conventionally used softwood or hardwood pulp, which is bleached or unbleached.

The solvent absorption (water absorption) time is measured by heating and drying at 60 ° C. for 24 hours or more in advance and then cooling in a desiccator to room temperature from a height of 10 mm from the surface of the sample to a glass dropper (outer diameter). 3.2mm, inner diameter 1.5
mm) of the solvent. After dripping,
It measures the time until the reflection of the solvent surface that has dropped on the sample surface disappears.
It is the average value of the times. The coating film type paint referred to in the present invention refers to a paint mainly composed of a resin having a relatively low molecular weight. The solvent absorption time of the decorative base material suitable for the coating type paint is preferably from 20 to 35 seconds, and is one of the parameters serving as conditions for selecting the paint to be used or the decorative base material. If the solvent absorption time is shorter than 20 seconds, the coating type paint will
This is not preferable because it causes unevenness of the coating film and requires an excessive amount of paint. If it is longer than 35 seconds, the productivity of the makeup process is lowered and the adhesion of the coating film is deteriorated. Depending on the solvent used, the absorption time tended to be water>ethanol> toluene.

As a production method, bleached chemical pulp that has been beaten in advance, other reinforcing fibers, calcareous raw materials, siliceous raw materials, and additives and water are mixed and dispersed to obtain a solid concentration of 5 to 5.
It can be manufactured by adjusting to about 15% by mass, laminating and forming into a plate shape by using a round-mesh type papermaking machine, further press-molding as necessary, autoclaving and curing.

In addition, bleached chemical pulp which has been beaten in advance,
It can be manufactured by mixing and dispersing other reinforcing fibers, calcareous raw materials, siliceous raw materials and additives with water to adjust the solid content concentration to about 30 to 50% by mass, performing dehydration press molding, and curing in an autoclave. it can.

The calcareous raw material referred to in the present invention has a solid content of 3%.
0 to 40% by mass, slaked lime, cement, or quicklime is used, and these can be used alone or in combination. The siliceous raw material in the present invention is 25 to 40% by mass in terms of solid content. Silica fine powder, fly ash and the like are used, and as the siliceous raw material for reducing bulk specific gravity, an amorphous siliceous raw material such as diatomaceous earth, silica fume, white carbon, and allophane can be used. The ratio between the calcareous raw material and the siliceous raw material is such that the CaO / SiO ₂ molar ratio is 0.4 to 1.2.
It is preferable to be within the range. More preferably 0.6 to
1.0.

The reinforcing fiber (including bleached chemical pulp) in the present invention is 1 to 10% by mass in terms of solid content, and in addition to the bleached chemical pulp, wood pulp or cellulose pulp, glass fiber, carbon fiber, rock wool Fiber, polypropylene, rayon, acrylic fiber, steel fiber, whisker, etc. can be used.
The content is preferably 1 to 10% by mass, more preferably 2 to 7% by mass.

The additive used in the present invention is 15 to 25% by mass in terms of solid content, and includes zonotolite, wollastonite, mica, calcium carbonate, talc, perlite, bentonite, sepiolite, gypsum, anhydrous gypsum, It is also possible to use fillers such as concrete waste materials and calcium silicate plate waste materials, or dimensional stabilizers and auxiliaries such as coagulants, defoamers, thickeners, and water reducers. Preferred dimensional stabilizers are zonotolite, wollastonite, calcium carbonate and gypsum.

The calcium silicate plate according to the present invention has an autoclave curing temperature of 120 to 220 ° C, preferably 1 to 220 ° C.
The temperature is 60 to 200 ° C and the curing time is 3 to 10 hours.

(Embodiment) An embodiment of the present invention will be described below. First, a bleached chemical pulp raw material is dispersed with water using a pulper to prepare a pulp slurry having a concentration of 3% by mass. Then, the slurry is beaten by a beater beater to adjust the freeness. Was prepared. Here, as the waste paper, medium-quality printing paper and high-quality printing paper cut into strips in advance by a shredder were used, and as unused cellulose pulp, bleached softwood pulp was used. The ignition residue of the medium quality printing paper used here was 6.5%, and the ignition residue of the high quality printing paper was 5.2%.
Met.

Next, slaked lime, silica sand, diatomaceous earth, and additives are added to a slurry containing a predetermined amount of the above-mentioned chemical pulp fiber so as to have a compounding ratio shown in Table 1, and the mixture is kneaded with water to about 7% by mass.
A slurry having a (solid content) concentration was formed into a plate shape by a papermaking method, and after further pressurizing, curing was performed at 180 ° C. for 6 hours by an autoclave, and the width was 40 cm and the length was 20
A fiber-reinforced calcium silicate molded article having a thickness of 0 cm and a thickness of 6 mm was obtained.

The molded body obtained in this way is heated at 105 ° C.
For 24 hours, and the bending strength was measured according to JIS A 1408 with the size of the specimen being No. 4 (30 cm × 25 cm). Further, the obtained molded body was cut into a size of 5 cm × 5 cm, and an iron pulling jig was adhered to both sides of the molded body with an adhesive, and the delamination strength was measured.

For the surface smoothness, the center line average roughness (Ra) at a cutoff of 2.5 mm was measured (n = 3) according to JIS B 0601 appendix using a surface roughness shape measuring instrument. And the average value was shown. Further, the state of fluffing on the surface when this was polished was observed. Solvent absorption time was 1 hour at a height of 10 mm from the surface of the compact.
Drops were dropped and the time until the reflection of the dropped solvent surface disappeared was measured (n = 3). Furthermore, 10cm × 10cm
A moisture-curable paint made by Hitachi Chemical Co., Ltd. was applied at 30 g / m ² as a paint type (low molecular weight) resin paint to a × 5 mm test body, heated and cured, and subjected to a paint film performance test.

Table 1 shows examples of the present invention. As can be seen from Table 1, the calcium silicate molded body obtained in this example had a bulk density of 800 kg / m ³ or more, a center line average roughness of 5.5 μm or less, and a solvent absorption (water absorption) time of 20 μm. From 35 seconds, and has excellent characteristics as a decorative base material. In addition, it has sufficient bending strength and delamination strength as a building interior material. Further, in the coating film performance test, the impregnation depth of the resin paint was 0.7 mm or less, and there was no problem in the coating film adhesion.

(Comparative Example) A molded article was produced in the same manner as in the example using newspaper waste paper and unused cellulose pulp at the compounding ratio shown in Table 2, and the same evaluation was performed. The result is
The center line average roughness of the calcium silicate molded product obtained as shown in Table 2 exceeded 5.5 μm, the surface smoothness was poor, and the solvent absorption time was as fast as less than 20 seconds. Further, in the coating film performance test, the impregnation depth of the resin coating exceeded 1.2 mm, the coating was absorbed by the base material, and a good coating was not obtained.

[0031]

As described above, the conventional calcium silicate molded article had problems of surface smoothness, solvent absorption (water absorption) rate, poor coating film adhesion and fuzzing, but was exposed as the reinforcing fiber of the present invention. The surface smoothness can be improved by blending chemical pulp at 10% by mass or less, preferably 2 to 7% by mass, more preferably 3 to 5% by mass, and the solvent absorption (water absorption) time can be adjusted to 20 to 35 seconds. Thus, a coating film type paint can be used, and a fiber-reinforced calcium silicate molded article having excellent performance as a decorative base material and having sufficient bending strength and delamination strength as an interior material for building can be obtained.

[0032]

[Table 1]

[0033]

[Table 2]

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C04B 111: 72 C04B 111: 72 (72) Inventor Masato Sakiyama 6-1, Kashihara, Ishioka-shi, Ibaraki Pref. F-term in the Building Materials Techno Laboratory Co., Ltd. (reference) 4G012 PA03 PA10 PA22 PE04 PE06 PE08 4G052 GA05 GA11 GA18 GA25 GB81 4G054 AA01 AA15 AA20 AC04 DA01

Claims (5)

[Claims] 1. A fiber reinforced calcium silicate comprising a reinforcing fiber containing a bleached chemical pulp and a solvent absorption (water absorption) time of 20 to 35 seconds. Molded body. 2. A bleached chemical pulp having a solid content of 2 to 7% by mass.
The fiber-reinforced calcium silicate molded product according to claim 1, wherein: 3. A bleached chemical pulp comprising 70 bleached chemical pulp.
The fiber-reinforced calcium silicate molded product according to claim 1 or 2, which is waste paper of printing paper containing at least 90% by mass, preferably at least 90% by mass. 4. A bleached chemical pulp which has been beaten in advance, a calcareous raw material, a siliceous raw material, a reinforcing fiber (excluding bleached chemical pulp), an additive and water are mixed and dispersed, and formed into a sheet by a papermaking method. The method for producing a fiber-reinforced calcium silicate molded article according to any one of claims 1 to 3, further comprising autoclaving after pressure molding as needed. 5. A bleached chemical pulp which has been beaten in advance, a calcareous raw material, a siliceous raw material, a reinforcing fiber (excluding bleached chemical pulp), an additive and water are mixed and dispersed, and the mixture is molded by a dehydration press and cured in an autoclave. 2. The method according to claim 1, wherein
4. The method for producing a fiber-reinforced calcium silicate molded product according to any one of items 1 to 3.